Removing the DC level of a signal.

Discussion in 'The Projects Forum' started by kahafeez, Jan 30, 2009.

  1. kahafeez

    Thread Starter Active Member

    Dec 2, 2008
    150
    0
    Hello Folks, i got this wave from a VCO which is operated at +5V and GND.....

    the frequency is 16.6Mega Hertz

    i need to remove the DC component of the signal..... meaning i need to bring the signals GND at DC gnd so that it waves about the DC 0V level....

    i thought a simple capacitor would do it bt it didnt really do it.... i used a 220uF capacitor as i didnt know what value to choose.... are there any rules for choosing the Capacitor's value..... plz state them.... or suggest a way to remove the dc level.... thanks....
     
  2. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    If you post your experimental capacitor circuit we should be able to get you fixed up.

    hgmjr
     
  3. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    220uF is much too large. A capacitor of that size will have lots of parasitics at that frequency.

    Try a 0.1uF or 10nF ceramic capacitor, with a 10k resistor to ground on the output side.
     
    tejasdj12 likes this.
  4. kahafeez

    Thread Starter Active Member

    Dec 2, 2008
    150
    0
    will try these values and post the results
     
  5. DickCappels

    Moderator

    Aug 21, 2008
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    632
    AND...add a resistor to ground so the signal will be around ground. When you look with a scope probe, the resistance of the scope probe to ground (usually 1 Meg Ohm or 10 Meg Ohm) will establish a ground reference. But when you remove the probe, the DC level for the signal will float to that of whatever you happen to connect it to.

    Try something like 100k for starters.
     
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